In the US, the number of women drug users diagnosed with AIDS continues to increase, and levels of sexual risk behaviors remain high. Theoretical and empirical work has indicated that drug using women's relationships with male sex partners are focal points of risky sexual behavior and drug use. To inform HIV prevention efforts, there is a need to explore women's relationship with their main sexual partners, and determine how relationship factors affect HIV risk. Drug using women (primarily African-American and Puerto Rican) will be recruited from the streets of East Harlem. Those who report use of crack/cocaine, injected drugs, of 360 couples (n=720) will complete structured interviews. In addition to demographic and socioeconomic characteristics, drug use, and HIV risk behaviors, the interview will measure: 1) dyadic factors (e.g., characteristics of the relationship, drug use patterns, interpersonal processes); 2) individual attributes (e.g., history of physical/sexual abuse, psychological functioning, HIV serostatus); and 3) situation specific variables in most recent sex events. HIV, hepatitis B, and Hepatitis C testing and counseling will be offered. Multi-variate statistical techniques will be used to determine the effects of dyadic factors, individual attributes, and their interaction on HIV risk behaviors. The prevalence of HIV, HBV, and HCV infections will be assessed, as will the couples will be compared in terms of drug use patterns, interpersonal processes, relationship satisfaction, and partner support. Results of this project will be used to develop interventions targeted at drug using couples to reduce HIV risk behaviors and assist those who are living with HIV.